4'-Flavonecarboxylic acid derivatives are already known. In particular, the Soci/ete Fisons filed a Belgian Pat. No. 815896 on June 4, 1974, describing in particular 4'-flavonecarboxylic acids substituted in the 7 position of the benzopyran ring by radicals such as H, halogen, alkyl, alkoxy, alkenyl, amino, hydroxyl, trifluoromethyl, cyano, alkylamino, alkoxyalkoxy, hydroxylalkoxy or nitro. These products exhibited antianaphylactic activities.